This application is directed to a solid-state luminaire consisting of an LED luminaire that features minimal glare and optimal heat dissipation through a thermal management system and glare reduction system.
Due to the increasingly widespread quest for energy savings, light emitting diodes (LEDs) have become more and more popular in the lighting industry. LEDs are so popular because of their small size, fast on-time and quick on-off cycling, relatively cool light, and high efficiency. LEDs present challenges for luminaire manufacturers, however, with respect to heat and glare.
In contrast to most other currently available light sources, LEDs radiate very little heat in the form of infrared radiation. Waste energy is dispersed as heat through the base of the LED. Typically, LED luminaires incorporate a plurality of LEDs and the heat given off can be substantial. Over-driving an LED in high ambient temperatures may result in overheating the LED array, eventually leading to device failure. Adequate heat dissipation is desirable to maintain the long life of which LEDs are capable.
For the most part, LED luminaires deal with the heat dissipation issue in one of two ways. Some luminaires incorporate air vents and complex heat sinks, sometimes involving fins on the exterior of the housing where they are visible to the consumer and aesthetically unappealing and often requiring complicated internal housing to allow for weatherproofing. Moreover, in many cases, because the number and size of LEDs affects heat dissipation requirements, the configuration and dimensions of the finned housing vary according to the number and size of the LEDs, which increases stocking requirements, makes it more difficult to substitute fixtures if lighting needs change, and increases architectural planning considerations. Those issues create a deterrent for businesses seeking to transition from existing non-LED luminaires to the greater efficiencies provided by LEDs.
Other luminaires simply do not provide adequate thermal management. If such fixtures are used for long periods of time, heat becomes a problem resulting in a likely shortening of the LED lifetimes and potential serious color shift of the devices.
Many LED luminaires also have problems with glare and/or the production of multiple shadows, since the light exiting each individual light-emitting diode is focused forward and not diffused. Traditionally, LED arrays are positioned similarly to other lamps in luminaires, such that the light flows directly from the lamp through the face of the fixture. This positioning allows for maximum light output, but it disregards the discomfort of the resulting glare. Generally when an LED luminaire is to be used as area lighting rather than point-source lighting, the issues of glare and shadowing have been treated in the manner typical of non-LED luminaires: by incorporating reflectors behind the lamp to diffuse the light and designing the housing to allow for the reflectors. Alternatively or in addition, a diffuser may be used.